Elucidation of alginate-drug miscibility on its crystal growth inhibition effect in supersaturated drug delivery system.

The objective of this study is to investigate the influence of drug-alginate miscibility on maintaining drug supersaturation. Using lovastatin, indomethacin, itraconazole as model drugs, drug-alginate miscibility was estimated by Hansen solubility parameters. The mechanism of drug-alginate miscibility on maintaining drug supersaturation was elucidated by microscopy, molecular mobility (T2), FTIR and X-ray crystallography. The influence of alginate properties on maintaining drug supersaturation was also examined. It was demonstrated that the capacity of alginate to maintain drug supersaturation was dependent on alginate-drug miscibility. Further mechanistic study revealed that alginate interacts with drugs via hydrogen bonding at different extent based on varied drug-alginate miscibility. Alginate could suppress drug molecular mobility and corresponding crystal growth inhibition. The properties of alginate also play an important role in maintaining drug supersaturation. In conclusion, alginate could be used as a potential crystal growth inhibitor, and the crystal growth inhibition effect depends on drug-alginate miscibility and alginate properties.

[Surgical treatment for posterior malleolus in complicated external rotation ankle fracture].

OBJECTIVE: To evaluate the indications, surgical techniques and clinical effects of the fixation of posterior malleolus in complicated external rotation ankle fractures and illuminate the importance of anatomical reduction and rigid internal fixation of posterior malleolar fracture. METHODS: From July 2007 to June 2009, 32 patients were treated with open reduction and internal fixation,involving 21 males and 11 females with an average age of 36 years old (ranged from 19 to 68 years old). According to Lauge-Hansen classification: 13 cases of pronation-external rotation type (IV), 7 and 12 cases of supination-external rotation type (III and IV). Postoperative functional exercise and regular follow-up were done and outcomes were assessed. RESULTS: All the patients were followed up,and the duration ranged from 7 to 20 months,with an average of 14.5 months. According to Ankle Hindfoot Clinical Rating System of the American Orthopaedic Foot & Ankle Society (AOFAS), 23 patients got an excellent result, 7 good, 2 fair, 0 poor. CONCLUSION: Anatomical reduction and rigid internal fixation of posterior malleolar fracture as well as early functional exercise have significance in restoring ankle joint function and reducing the incidence of traumatic arthritis.